1. Field of the Invention
The present invention relates to testing system for subjecting objects to vibrational conditions. More particularly, this invention is directed to vibroacoustically coupled testing systems for subjecting various types of structures, devices and/or subjects to simulated environmental vibrational conditions.
2. Description of Related Art
Vibration testing is important to many technologies, as for example, testing building structures, aircraft, vehicles and components of all kinds. Testing techniques have become increasingly precise and are extended to deal with problems in such fields as the design of machines, medical diagnostics/treatments and electronic component reliability.
Numerous vibrational testing systems are known in the art for evaluating various structures and devices. In particular, the screening and testing of assembled electronic and mechanical devices and components for defects in design make extensive use of such systems.
One such testing system is the mechanical shake table. This system utilizes a mechanical vibratory system such as, for example, a crank mechanism connected to a mounting table for imparting a single frequency vibration to a test object along a single axis of operation. Such systems are limited in their capabilities because variations and adjustments in vibrational amplitude are usually made at rest and, depending on the size of the test object, are extremely costly and expensive to operate. Such systems are typically unable to adapt to changes in ambient conditions including temperature and humidity resulting in considerable adaptive or maintenance requirements.
In another known type of shake table, electrodynamic means are utilized to accelerate the mounting table and the test object affixed thereon to produce a range of amplitude and frequency necessary for testing. While these systems are more readily adjustable, they are still quite expensive to purchase and maintain.
A further vibrational testing system known in the art makes use of voice coil technology to subject a test object to a range of amplitude and frequency to simulate environmental and/or test conditions. These systems are complex, expensive and require extensive support facilities for operation and use. For example, known voice coil technology requires extensive mounting space, an existing source of high pressure air and high amperage.
Further, objects to be tested using this technology have specific load requirements which serve to limit operation and configuration changes in the testing system. Limitations on these systems include high power consumption, limited frequency range (5-2000 Hz) and low reliability during periods of continuous use.
Hydraulic testing systems also are utilized for environmental simulation. These systems have an even more limited frequency range (0-200Hz) and require similar support facilities for operation and maintenance as the voice coil technology systems. The known hydraulic testing systems typically have very high power consumption, require frequent maintenance and have low reliability under frequent usage.
Therefore, it would be highly desirable to have a vibrational test system for reliably simulating a wide variety of dynamic environmental conditions without the need for extensive support facilities and high power consumption.
Accordingly, it is one object of the present invention to provide a vibrational test system utilizing acoustic technology combined with fluid dynamics to reliably create controlled and tuned environmental dynamic conditions.
It is a further object of the present invention to provide a vibrational testing system which simulates a wide variety of dynamic conditions with relatively low power consumption and minimal space requirements.
It is also an object of the present invention to provide a vibrational testing system which subjects test objects to various dynamic conditions without the need for extensive support facilities.
These and other highly desirable and unusual results are accomplished by the present invention in a vibration test system utilizing acoustic technology combined with fluid dynamics to create an environment in which "chaotic" or random harmonic motion can be regulated and tuned.
Objects and advantages of the invention are set forth in part herein and in part will be obvious therefrom, or may be learned by practice with the invention, which is realized and attained by means of the instrumentalities and combinations pointed out in the appended claims. The invention consists of novel parts, constructions, arrangements, combinations, steps and improvements herein shown and described.